I'm working through Vance's Progressive Repertoire, Volume 3. In the Thomas Gavotte, Measure 8 presents a challenge with this 32nd note figure at the octave on the G string, which goes: F#-G-F#-G-F#. It is to be played with the 2nd and third finger. I can't play this anywhere near tempo, and the sound of my G is weak. Not much strength/control in the 3rd finger. I'm use to playing that G as a harmonic. Any suggestions?